Conventionally, a technology has been known that detects an emergency brake operation by a stepping amount and a stepping speed of a brake, and lowers a detection reference (threshold) for the emergency brake operation in a brake apparatus to execute a brake assist while a risk becomes higher for a collision between the brake-operated vehicle and an obstacle (for example, Patent Document 1). This makes it possible, in an emergency where the risk is high for the vehicle to collide with the obstacle, to execute the brake assist for avoiding the collision with the obstacle even if a stepping on the brake pedal is shallow due to a judgment error or a skill problem of a driver.